how do you show selected mesh in blender's outliner?
It is possible to filter the displayed objects in the Outliner by their state. Click on the filter icon and change the object state filter to Selected. The outliner should now only display the selected objects.


If the particular objects are deeply nested in collections and you don't want to step through the hierarchy, disable the Collection filter checkbox. This will display the objects without their collection hierarchy, just one after the other in the outliner.